Engine loses power, backfires and won't start

Sjmmarsh · Post by **Sjmmarsh** » Sat Mar 01, 2014 4:54 pm

I took my Auto S3 out for a run today as it is a while since the weather was good. It started up OK after cranking for a little while, did a big backfire and then ran OK on choke, albeit a little rough sounding
(maybe that is just because I haven't heard it running for 3 months).

All was Ok for the first 6 miles, but then I noticed that the engine was a little hesitant to pull going uphill but got a little better with 1 notch of choke reapplied.

About 2 miles later, I had real problems pulling away from a junction and going uphill - there was no real power and some violent misfires from the engine, so I pulled in to the side of the road - the engine then stalled and died. Checking the engine, I noticed that some of the vacuum/air pipes to the air filters had come off - I reconnected them, but am not 100% sure they are refitted correctly.

The car would not restart - it turned over, coughed very occasionally, but would not catch.

It wouldn't restart - it just turned over, with the occasional cough, so I have recovered the E-Type to my local garage (who will be surprised on Monday morning as I couldn't warn them, and they haven't seen the E before...)

Does anyone have a diagram that shows where all the tubes are supposed to go into the air cleaner housing? I have done a comparison between both sides (allowing for the fact that one is upside down); the main difference is that on one side the clear tube that goes into the trumpet at the front is not connected to anything, whereas the other side it goes back into the cleaner between the Strombergs and the tube from the thermostatic valve is left dangling.. A diagram would be a great help, but I can't find anything in the Repair Operation Manual.

Finally - does anyone know what the likely problem is? I need to learn how to keep the V12 in tune by the sound of it!

Steve

abowie · Post by **abowie** » Sat Mar 01, 2014 8:57 pm

I have no personal experience with V12's but the OPUS ignition system fitted to them can apparently cause problems with poor running and not starting when hot.

See http://www.reopusignition.com/index.html

Sjmmarsh · Post by **Sjmmarsh** » Sat Mar 01, 2014 10:58 pm

Thanks Andrew

It had a replacement unit last summer, so I hope it is still OK, but they do seem pretty unreliable! I'll check it out.

Steve

MarekH · Post by **MarekH** » Sun Mar 02, 2014 7:53 am

If it gets better "with a little choke" as you report then that suggests fuel isn't arriving at the carburettors in sufficient quantity.

kind regards
Marek

MarkG · Post by **MarkG** » Sun Mar 02, 2014 9:27 pm

Sounds more like a fueling problem to me. Likely a failed fuel pump. Can you hear the fuel pump in the rear wing ticking when the ignition is on? If so is it ticking really fast? If so you are out of fuel or you have a blocked fuel line. If it is a steady tick then can you hear the return valve next to the passenger side front carb ?

You do not need to worry too much about those vacuum pipes running into the air cleaners. They are only for emissions during cold running

D COUPE · Post by **D COUPE** » Mon Mar 03, 2014 8:51 am

If your car has been kept in a damp environment I would check the distributor cap for moisture.

I have personnel experience of this and the symptoms you described are just how it goes OK for 5 mile then no power and eventually failing.

The cure is to warm the inside of the distributor cap or fit a spare. The condensation will disperse and it will be back to normal.

Hope this helps

DC

calum · Post by **calum** » Fri Mar 07, 2014 9:30 pm

Hi.

Mine was plumbed up badly when I got it so I did a bit of research on what goes where.

As far as I could gather, for UK spec the pipes run as follows:

The rear inlet manifolds tapping is plumbed to thermostatic valve on air cleaner.
The other port on the thermostatic valve is plumbed to the flapper valve in the intake horn.

Front inlet manifolds tapping - blanking plugs fitted.

Right hand bank (again from sitting in driving seat looking forwards)

See this diagram:

http://www.sngbarratt.com/CatalogueProd ... 16583&b=GB

I ordered and used these blanking plugs in 4mm:
http://www.ebay.co.uk/itm/Silicone-Hose ... 2c72149719

and this tubing

http://www.ebay.co.uk/itm/4mm-x-10mm-5- ... 3cb111cb8a

Cheers,

Calum

Sjmmarsh · Post by **Sjmmarsh** » Fri Mar 07, 2014 10:34 pm

Thanks Calum - I'll check the plumbing tomorrow.

The car is now back from the garage - 12 new plugs, a compression test (all fine) and a new distributor cap because of cracking and tracking and the car is back to normal.

I took longer for the garage to diagnose because the cap has only been on the car for less than a year and 800 miles, so looked brand new.

At least I know what to look out for next time.

Steve

calum · Post by **calum** » Sat Mar 08, 2014 7:41 pm

Hi.

If you had a backfire that was big enough to blow the piping off it may be a wise precaution to check the stromberg diaphragms.

Cheers

Calum

Sjmmarsh · Post by **Sjmmarsh** » Sat Mar 08, 2014 10:02 pm

Thanks Calum - I'm new to this - where should I start on checking the Stromberg diaphragm?

Steve

iani · Post by **iani** » Sun Mar 09, 2014 9:31 am

Sjmmarsh wrote:Thanks Calum - I'm new to this - where should I start on checking the Stromberg diaphragm?

Steve

Steve,

Take the carb dashpot off (4 screws) then lift the piston tube upwards, this will come off with the diaphragm and needle. Gently inspect the diaphragm all the way round for splits or tears, if you find any then it needs replacing (4 screws, note locator tag on installation) If no tears are found replace the needle/piston assembly, noting the tag on the outer edge of the diaphragm fits into a slot on the carb body. Evenly tighten the 4 dashtop screws, lift the piston through the air inlet 1/4" and check it drops easily, if it binds then your screws aren't even, it pays to be thorough here. Now repeat this for the other three carbs. Once complete, top up the dashpots with your favourite oil, I use Millers SU carb oil, some use 20/50 and some use ATF apparently, fill just enough so that the plunger feels resistance 1/4" above top of dashtop.

Ian (I don't have an S3 but I do have a Stag with 175CD Strombergs)

calum · Post by **calum** » Sun Mar 09, 2014 11:50 am

A pictorial guide can be found here:

http://www.msvcr.com/e107_plug_ins/cont ... ?content.8

and diaphragms are available from barratts or eBay or various other places. Just search for 'stromberg 175 diaphragm'.

Cheers

Calum

Lambo911 · Post by **Lambo911** » Tue Jul 15, 2014 10:13 am

Did you ever find out what the problem was?

My 72 V12 S3 e-type UK car hasn't been used for about 10 years. I can get it to start and tick over on the choke but if I try and rev it up it will die. Sometimes it won't start at all, just turns over but if I fiddle with the wiring between the lucas box and the dizzy or coil it starts.
It sounds like an Opus problem so rather than messing around I was thinking I should just change it for a Reopus H and also the coil while I'm at it.

Even if it isn't that I'm guessing it is a worthwhile upgrade ?

V12 Epyte · Post by **V12 Epyte** » Wed Jul 16, 2014 5:56 am

I also had starting prolems. I have just fitted the Reopus upgrade, didnt make much difference to the starting issue although the engine does run alot smoother now. The Reopus was sent from New Zealand, arrived within a week. We decided to replace the carb diaphrams and Paul Brown also had the carbs apart to check and adjust the choke settings. I also cleaned up the connections with contact cleaner which improved things . Now starts prefectly and the car is running better than it ever has.

Sjmmarsh · Post by **Sjmmarsh** » Wed Jul 16, 2014 6:11 pm

Lambo911

It was the dizzy cap that was tracking and so causing a misfire (several!). A new dizzy cap got it running again.

Steve

Lambo911 · Post by **Lambo911** » Fri Jul 18, 2014 8:42 am

Even though they look ok I'm just wondering if it is worth replacing the cap, rotor arm, leads and coil anway just so I'll know I'm starting with a fresh ignition set up?

I have a Reopus H on order so that will arrive next week hopefully.

The car is being a bit wierd, there is no spark, then the next moment there is and it starts straight up. It was ticking over yesterday then just died. Definitely an ignition glitch somewhere !

Sjmmarsh · Post by **Sjmmarsh** » Sat Jul 19, 2014 1:49 am

Lambo911 sounds like there is a problem somewhere in the ignition system - I'd suspect the leads to the dizzy rather than the dizzy itself as your problem sounds like no spark at all, rather than a spark going to the wrong plug... mine definitely sounded very sick and was violently rough before it died.

Steve

Lambo911 · Post by **Lambo911** » Mon Aug 04, 2014 7:43 pm

My Reopus arrived and is now fitted. I did get stung for ?35 worth of import tax.

The car fired up straight away and I have a much stronger spark now.

I then followed the workshop manual for balancing the carbs and it's running nicely now.

Still haven't driven it as now need to replace the clutch master and slave cylinders but they should arrive tomorrow and with a bit of luck I'll get it out on the road this weekend !!

I'm just hoping I'm not disappointed with the driving experience. I've never driven an E-Type before and I'm a bit worried it will be a bit of a barge !

Sjmmarsh · Post by **Sjmmarsh** » Tue Aug 05, 2014 5:41 am

Good luck Lambo911!

The E handles quite nicely, although you may find the bonnet gets a bit of getting used to - there is so much of it. Take it easy over bumpy roads as you may find the car is riding low if the suspension has not been tended too. The noise of the exhaust grounding at speed is not nice.....

Steve

V12 Epyte · Post by **V12 Epyte** » Tue Aug 05, 2014 5:52 am

I brought my Reopus recently, I wasn't charged any import tax?

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Engine loses power, backfires and won't start

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